Ion Beam Sample Preparation Apparatus and Methods

ABSTRACT

Ion beam sample preparation apparatus and methods are described. The apparatus has disposed in a vacuum chamber at least one tilting ion beam irradiating means with intensity control, a rotation stage with rotation control, a sample holder, and an adjustable positioning stage that has two axes of positional adjustment that are operable to move the region of the sample being prepared by the ion beam relative to the ion beam. The apparatus may also include a vacuum-tight optical window for observing the sample and a shutter for protecting the optical window from debris while the sample is prepared in the ion beam. The apparatus may also include an instrument controller responsive to the state of the apparatus and to the condition of the sample and is operable to control the preparation of the sample.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of prior filed non-provisionalutility application Ser. No. 13/949,318 filed Jul. 24, 2013.Non-provisional utility application Ser. No. 13/949,318 claims thebenefit of prior filed provisional Application No. 61/676,368 filed Jul.27, 2012. Application Ser. No. 13/949,318 is incorporated herein byreference. Application No. 61/676,368 is incorporated herein byreference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable.

DESCRIPTION OF ATTACHED APPENDIX

Not Applicable.

BACKGROUND

The present disclosure relates to the use of one or more ion beams toprepare materials for microscopic observation or spectroscopic analysis.Microscopic observational techniques include, but are not limited to,optical microscopy, scanning electron microscopy (SEM), transmissionelectron microscopy (TEM), scanning transmission electron microscopy(STEM), and reflection electron microscopy (REM). Spectroscopic analysistechniques include, but are not limited to, x-ray micro-analysis,reflection electron energy-loss spectroscopy (REELS), electronback-scattered diffraction (EBSD), x-ray photoelectron spectroscopy(XPS), and Auger electron spectroscopy (AES). Materials to be viewedunder any microscopic technique may require processing to produce asample suitable for microscopic examination.

Transmission electron microscopy (TEM) is an important technique forstudying the detailed microstructure of many materials. The preparationof samples for atomic resolution TEM is very demanding, requiring afinal sample that is very thin (i.e. <50 nanometers) and free fromartifacts. Typically, sample preparation involves initial slicing,sectioning, and mechanical thinning to produce a relatively thin (i.e.100-200 micrometers) disk of sample material. Ion beam milling of thesample may then be employed to further thin, smooth, and expose regionsof interest in the sample for later TEM study, typically producing asample with a thickness of 50 nanometers.

Ion beam milling of a material can produce samples that are well suitedfor microscopic examination. An ion beam irradiating device maygenerate, accelerate, and direct a beam of ions toward a sample. Theimpact of ions on the sample will sputter material away from the area ofion impact. Furthermore, the sample surface may be polished by the ionbeam to a substantially smooth condition, further enhancingobservational properties of the sample. Regions of interest in thesample may be exposed and polished by the use of ion beams, thus makinga suitable observational sample from the material under investigation.

Ion beam systems used to mill samples destined for TEM analysistypically expose an interface or produce a sample with an electrontransparent region. Many of these systems have rotating samples andfixed beams, so that the beams may strike the sample from multipledirections. This provides for more uniform milling of a sample bycompensating for the shadowing of certain regions that may happen due tothe nonuniform topology of the sample surface. In the typical systemused for ion beam milling, material is removed most quickly from thesample by the ion beam in the region of the sample described by theintersection of the rotation axis of the sample with the center of theion beam itself. It is often difficult to position a sample in the ionbeam system so that the specific region of interest lies at the centerof rotation. Some amount of trial and error may be expected when tryingto target a specific region of interest in the ion beam samplepreparation process.

Important considerations to users of the ion beam milling techniqueinclude: reducing or minimizing the time and effort the user is occupiedin processing the sample; reducing or minimizing the number of stepswhere delicate samples are directly handled and at risk for damage, suchas during mounting to sample holders for processing or analysis;reducing or minimizing the time and effort the user is occupiedtransferring the sample into the ultimate analysis equipment (imaging orspectroscopy), and aligning the coordinates of the prepared sampleregion to the ultimate analysis equipment prior to analysis; ensuringhigh quality and high probability of success in processing and imagingthe sample; reducing or minimizing the time that the ion millingequipment and sample mounting equipment are occupied for each sample;and ensuring high-quality microscopy observation of the sample duringsample mounting and ultimate analysis by reducing the working distancerequired between the sample and the objective or probe-forming lens usedfor observation.

In consideration of the foregoing points, it is clear that embodimentsof the present disclosure confer numerous advantages and are thereforehighly desirable.

SUMMARY

The present disclosure is directed to ion beam sample preparationapparatus and methods for using the disclosed apparatus to preparesamples for later observation. Features of the disclosure enableadjustable multi-axis micro-positioning of a sample within the ion beam,thereby conferring numerous advantages in finding, spotting, andexposing a region of interest within the sample being prepared.Additional features of the disclosure provide benefits in: minimizingthe handling of delicate samples, improving the diagnostic viewing ofthe sample undergoing preparation, and improving the overall efficiencyof the ion beam sample preparation process. Additional features of thedisclosure provide for instrumented control of the sample preparationapparatus using sample imaging.

An apparatus for preparing a sample using an ion beam according to anembodiment of the present disclosure comprises: a first ion beamirradiating means disposed in a vacuum chamber and directing a first ionbeam toward said sample, said first ion beam irradiating meansoperatively coupled to a first ion beam intensity control means, saidfirst ion beam having a first central ion beam axis, said first ion beamintensity control means operative to produce at least two different ionbeam intensities; a first ion beam tilt control means operativelycoupled to said first ion beam irradiating means and configured toprovide at least two different tilt angles of said first ion beamirradiating means; a rotation stage disposed inside said vacuum chamberhaving a rotation axis and coupled to a rotation drive, said rotationdrive operative to rotate said rotation stage around said rotation axis,said rotation axis being positioned to intersect a portion of said firstion beam; an adjustable positioning stage that is adjustably coupled tosaid rotation stage, said adjustable positioning stage comprising asample holder retention means configured to releasably retain a sampleholder, said sample holder comprising: a sample holder retained portion;at least one sample support arm configured to support said sample; and asample holder bore that allows an unobstructed line-of-sight through theentirety of sample holder retained portion onto said sample being heldby said one or more sample support arms; said sample holder furthercharacterized as positioning said sample so that said rotation axis andsaid first central ion beam axis both intersect substantially the sameportion of said sample that is being prepared in said first ion beam;said sample holder further characterized in that no portion of saidsample support arm is intersected by said rotation axis while saidsample is being prepared by said ion beam; said adjustable positioningstage further comprising: a first position adjustment means configuredto move said adjustable positioning stage along a first adjustment axis;and, a second position adjustment means configured to move saidadjustable positioning stage along a second adjustment axis; avacuum-tight optically-transparent vacuum window disposed to permitdirect, line-of-sight viewing from outside the vacuum chamber of atleast a portion of said sample while said sample is being prepared insaid first ion beam; and, a shutter means disposed between said vacuumwindow and said sample holder; said shutter means further characterizedas having a shutter closed position in which said vacuum window issubstantially sealed from the interior of said vacuum chamber, and, saidshutter means further characterized as having a shutter open positionthat permits direct, line-of-sight viewing from outside the vacuumchamber of at least a portion of said sample while said sample is beingprepared in said first ion beam; a first illumination source directinglight through said sample holder bore toward said sample and furthercharacterized in that at least a portion of the light emitted by saidfirst illumination source strikes at least a portion of said samplewhile said sample is being prepared in said first ion beam; and, asample viewing means having an optical axis directed toward the regionwhere said first central ion beam axis substantially intersects saidrotation axis, said sample viewing means further characterized asproviding a magnified and substantially focused view of the region ofsaid sample being prepared by said first ion beam.

In a related embodiment the first illumination source is furthercharacterized as producing substantially monochromatic light. In anotherrelated embodiment the apparatus further comprises: a secondillumination source directing light toward said sample and furthercharacterized in that at least a portion of the light emitted by saidsecond illumination source strikes at least a portion of said samplewhile said sample is being prepared in said first ion beam. In anotherrelated embodiment the apparatus further comprises: a sample imagingmeans that is operative to capture one or more images made available bysaid sample viewing means.

In another related embodiment the apparatus the sample imaging means isoperative to save one or more previously captured images. In anotherrelated embodiment the is further characterized in that the sampleimaging means is operative to save one or more unique indicia with eachsaid one or more previously captured images. In another relatedembodiment of the apparatus the sample imaging means is operative todisplay said one or more previously captured images. In another relatedembodiment the apparatus is further characterized in that the sampleimaging means is operative to receive said one or more unique indiciaand display said one or more previously captured images correspondingwith said one or more unique indicia. In another related embodiment theapparatus is further characterized in that the sample imaging means isoperative to receive one or more annotations identifying the locationone or more regions of interest within said one or more previouslycaptured images and saving said one or more annotations with said one ormore previously captured images.

An apparatus for preparing a sample using an ion beam according to anembodiment of the present disclosure comprises: a first ion beamirradiating means disposed in a vacuum chamber and directing a first ionbeam toward said sample, said first ion beam irradiating meansoperatively coupled to a first ion beam intensity control means, saidfirst ion beam having a first central ion beam axis, said first ion beamintensity control means operative to produce at least two different ionbeam intensities; a first ion beam tilt control means operativelycoupled to said first ion beam irradiating means and configured toprovide at least two different tilt angles of said first ion beamirradiating means; a rotation stage disposed inside said vacuum chamberhaving a rotation axis and coupled to a rotation drive, said rotationdrive operative to rotate said rotation stage around said rotation axis,said rotation axis being positioned to intersect a portion of said firstion beam; an adjustable positioning stage that is adjustably coupled tosaid rotation stage, said adjustable positioning stage comprising asample holder retention means configured to releasably retain a sampleholder, said sample holder comprising: a sample holder retained portion;at least one sample support arm configured to support said sample; and asample holder bore that allows an unobstructed line-of-sight through theentirety of sample holder retained portion onto said sample being heldby said one or more sample support arms; said sample holder furthercharacterized as positioning said sample so that said rotation axis andsaid first central ion beam axis both intersect substantially the sameportion of said sample that is being prepared in said first ion beam;said sample holder further characterized in that no portion of saidsample support arm is intersected by said rotation axis while saidsample is being prepared by said ion beam; said adjustable positioningstage further comprising: a first position adjustment means configuredto move said adjustable positioning stage along a first adjustment axis;and, a second position adjustment means configured to move saidadjustable positioning stage along a second adjustment axis; avacuum-tight optically-transparent vacuum window disposed to permitdirect, line-of-sight viewing from outside the vacuum chamber of atleast a portion of said sample while said sample is being prepared insaid first ion beam; and, a shutter means disposed between said vacuumwindow and said sample holder; said shutter means further characterizedas having a shutter closed position in which said vacuum window issubstantially sealed from the interior of said vacuum chamber, and, saidshutter means further characterized as having a shutter open positionthat permits direct, line-of-sight viewing from outside the vacuumchamber of at least a portion of said sample while said sample is beingprepared in said first ion beam; a first illumination source directinglight toward said sample and further characterized in that at least aportion of the light emitted by said first illumination source strikesat least a portion of said sample while said sample is being prepared insaid first ion beam; a sample viewing means having an optical axisdirected toward the region where said first central ion beam axissubstantially intersects said rotation axis, said sample viewing meansfurther characterized as providing a magnified and substantially focusedview of the region of said sample being prepared by said first ion beam;a sample imaging means that is operative to capture one or more imagesmade available by said sample viewing means, said sample imaging meansfurther characterized as being operatively coupled to a firstcommunications channel and being responsive to said communicationschannel for capturing one or more images and communicating one or morecaptured images over said first communications channel; and, aninstrument controller that is operative to: communicate with and controlthe actions of said sample imaging means through said firstcommunications channel; communicate with and control the actions of ashutter actuation means through a second communications channel, saidshutter actuation means being operative to move said shutter meansbetween said shutter open position and said shutter closed position inresponse to communications received through said second communicationschannel.

In a related embodiment the apparatus is further characterized in thatthe instrument controller is operative to communicate with and controlthe actions of said first ion beam intensity control means through athird communications channel, the first ion beam intensity control meansbeing operative to change the intensity of said first ion beam inresponse to communications received through said third communicationschannel. In another related embodiment the apparatus is furthercharacterized in that the instrument controller is operative tocommunicate with and control the actions of said first ion beam tiltcontrol means through a fourth communications channel, said first ionbeam tilt control means being operative to change the intensity of saidfirst ion beam in response to communications received through saidfourth communications channel. The apparatus may be furthercharacterized in that the instrument controller is operative tocommunicate with and control the actions of said rotation drive througha fifth communications channel, said rotation drive being operative tochange the position of said rotation stage in response to communicationsreceived through said fifth communications channel.

In a related embodiment the apparatus is further characterized in that:the instrument controller is operative to communicate with and controlthe actions of said first ion beam intensity control means through athird communications channel, the first ion beam intensity control meansbeing operative to change the intensity of said first ion beam inresponse to communications received through said third communicationschannel; the instrument controller is operative to communicate with andcontrol the actions of said first ion beam tilt control means through afourth communications channel, said first ion beam tilt control meansbeing operative to change the intensity of said first ion beam inresponse to communications received through said fourth communicationschannel; and, the instrument controller is operative to communicate withand control the actions of said rotation drive through a fifthcommunications channel, said rotation drive being operative to changethe position of said rotation stage in response to communicationsreceived through said fifth communications channel.

In a related embodiment the apparatus is further characterized in thatthe instrument controller is operative to extract one or more featuresfrom one or more captured images, and in response to one or moreextracted features said instrument controller is operative to control atleast one of the group consisting of said sample imaging means, saidshutter actuation means, said first ion beam intensity control means,said first ion beam tilt control means, and said rotation drive. Inanother related embodiment the apparatus may be further characterized inthat the instrument controller is operative to extract a feature fromone or more captured images that indicates that said sample isperforated, said instrument controller being further characterized asbeing operative to respond to the extraction of said feature by causingsaid first ion beam intensity control means to change the ion beamintensity. In another related embodiment the apparatus may be furthercharacterized in that the instrument controller is operative to extracta feature from one or more captured images that represents a stoppingcondition, and in response to extracting said stopping condition saidinstrument controller is operative to cease preparing said sample insaid first ion beam.

In a related embodiment the apparatus is characterized in that theinstrument controller is operative to extract a feature from one or morecaptured images that indicates that said sample is approachingperforation, said instrument controller being further characterized asbeing operative to respond to the extraction of said feature by causingsaid first ion beam intensity control means to change the intensity ofsaid first ion beam. In another related embodiment the apparatus theapparatus may be further characterized in that the instrument controlleris operative to: extract a feature from one or more captured images thatis representative of one or more interference rings; and, extract afeature from one or more captured images that is representative of achange over time of said one or more interference rings; said instrumentcontroller being further characterized as being operative to respond tothe extraction of said features by causing said first ion beam intensitycontrol means to change the intensity of said first ion beam. In anotherrelated embodiment the apparatus may be further characterized in thatthe rotation drive is operative to provide a rotation angle to theinstrument controller, and the instrument controller is operative tocapture an image and annotate said captured image with said rotationangle.

In a related embodiment the apparatus is characterized in that therotation drive is operative to provide a rotation angle to theinstrument controller, and the instrument controller is operative tocapture one or more images at substantially the same rotation angle. Inanother related embodiment the apparatus may be further characterized inthat the instrument controller is operative to use one or moreacquisition parameters to control at least one from the group consistingof said sample imaging means, said shutter actuation means, said firstion beam intensity control means, and said first ion beam tilt controlmeans; and, said rotation drive, when said shutter means is in saidshutter closed position, and the apparatus is further characterized inthat the instrument controller is operative to use one or moreacquisition parameters to control at least one of the group consistingof said sample imaging means, said shutter actuation means, said firstion beam intensity control means, said first ion beam tilt controlmeans, and said rotation drive, when said shutter means is in saidshutter open position.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 shows schematic cross sectional view of an ion beam samplepreparation apparatus according to the present disclosure.

FIG. 2 shows schematic cross sectional view of an ion beam samplepreparation apparatus according to another embodiment of the presentdisclosure.

FIG. 3 shows a perspective view of a sample holder holding a sample.

FIG. 4 shows a perspective view of a rotation stage coupled to anadjustable positioning stage prior to retaining a sample holder.

FIG. 5 shows a perspective view of a rotation stage coupled to anadjustable positioning stage with the sample holder in a retainedposition.

FIG. 6 shows a perspective view of the apparatus of FIG. 5 in which apositioning stage cover has been placed on the rotation stage.

FIG. 7A shows a schematic cross sectional view of an ion beam samplepreparation apparatus according to another embodiment of the presentdisclosure having features that enable viewing of the sample while it isbeing prepared by the ion beam, with shutter means shown in a shutterclosed position.

FIG. 7B shows a schematic cross sectional view of the apparatus of FIG.7A with shutter means shown in a shutter open position.

FIG. 8A shows a schematic cross sectional view of an ion beam samplepreparation apparatus according to another embodiment of the presentdisclosure featuring a rotation stage lifting means. The apparatus ofFIG. 8A is shown with a rotation stage lifting means in a raisedposition and the shutter means in a shutter open position.

FIG. 8B shows the apparatus of FIG. 8A with the chamber cover in placeand creating a loading chamber.

FIG. 8C shows the apparatus of FIG. 8A with the rotation stage liftingmeans in a processing position and the shutter means in a shutter closedposition.

FIG. 8D shows the apparatus of FIG. 8A with the rotation stage liftingmeans in a processing position and the shutter means in a shutter openposition and ready for observation of the sample from outside the vacuumchamber through the vacuum window.

FIG. 9 shows a schematic cross sectional view of an ion beam samplepreparation apparatus according to another embodiment of the presentdisclosure featuring an instrument controller which is communicatingwith and controlling the systems of the apparatus.

FIG. 10 shows an operational flow chart of a periodically executedobservation and control process operating in the apparatus of FIG. 9.

FIG. 11 shows an operational flow chart of the image acquisition processoperating in the apparatus of FIG. 9.

FIG. 12 shows a flowchart of a beneficial aspect of another embodimentaccording to the present disclosure.

LIST OF REFERENCE NUMBERS APPEARING IN THE FIGURES

-   -   2—ion beam sample preparation apparatus    -   6—sample    -   8—sample peripheral edge    -   9—sample surface    -   9 a, 9 b—first, second sample surface    -   10—vacuum chamber    -   16—loading chamber    -   18—chamber cover    -   20—ion beam irradiating means    -   20 a, 20 b—first, second ion beam irradiating means    -   22—central ion beam axis    -   22 a, 22 b—first, second central ion beam axis    -   24—ion beam intensity control means    -   24 a, 24 b—first, second ion beam intensity control means    -   26—ion beam tilt control means    -   26 a, 26 b—first, second ion beam tilt control means    -   40—rotation stage    -   42—rotation drive    -   44—rotation axis    -   45—adjustable positioning stage    -   46 a, 46 b—first, second adjustment axis    -   47—positioning stage cover    -   48 a, 48 b—first, second position adjustment means    -   49—sample holder retention means    -   50—sample holder    -   51—sample holder retained portion    -   52—sample support arm    -   52 a, 52 b—first, second sample support arm    -   54—sample holder bore    -   60—lighting source    -   60 a, 60 b—first, second illumination source    -   70—sample viewing window    -   71—sample viewing means    -   72—shutter means    -   73—shutter actuation means    -   74—sample imaging means    -   76—optical axis    -   80—rotation stage lifting means    -   86—raised position    -   88—processing position    -   90—vacuum pump means    -   92—pumping manifold    -   92 a, 92 b—first, second pumping manifold    -   100—instrument controller    -   102 a,102 b,102 c,102 d,102 e—first, second, third, fourth, and        fifth communications channel    -   200, 202, 204, 206, 208, 210, 212, 214, 216, 218—process steps    -   300, 302, 304, 306, 308, 310, 312, 314, 316—process steps    -   400, 402, 404, 406, 408, 410—process steps

DESCRIPTION

Embodiments of the present disclosure provide ion beam samplepreparation apparatus and methods capable of producing a thin, polished,electron-transparent region from a sample. In particular, the presentdisclosure describes a multi-axis micro-positioning stage that improvesthe ability to view and process a region of interest in the sample. Thedisclosed improvement has the benefits of: minimizing sample handling;improving the ability to position a region of interest that is withinthe sample in the center of the ion beam, thereby improving processingefficiency; and, improving the ability to position the sample fordiagnostic imaging while the sample is being prepared in the ion beam.

Turning now to FIG. 1, an embodiment of an ion beam sample preparationapparatus 2 according to the present disclosure is shown comprising: avacuum chamber 10 in which a sample 6 is prepared; chamber cover 18which seals vacuum chamber 10 from the outside atmosphere; vacuum pumpmeans 90 and pumping manifold 92 which together bring vacuum chamber 10to vacuum levels appropriate for ion beam milling; an ion beamirradiating means 20, which creates and directs an ion beam having acentral ion beam axis 22 toward sample 6; an ion beam intensity controlmeans 24, which is operative to provide at least two different ion beamintensities; an ion beam tilt control means 26, which is operative toprovide at least two different tilt angles of ion beam irradiating means20; a rotation stage 40 disposed inside vacuum chamber 10 having arotation axis 44 and a rotation drive 42; an adjustable positioningstage 45 which is adjustably coupled to rotation stage 40, theadjustable positioning stage 45 comprising: a sample holder retentionmeans 49 configured to releasably retain sample holder 50, the sampleholder 50 comprising: a sample holder retained portion 51 and at leastone sample support arm 52 by which sample 6 may be held; support arm 52being further characterized as positioning sample 6 so that rotationaxis 44 and central ion beam axis 22 both intersect substantially thesame portion of sample 6 while the sample is being prepared in the ionbeam, and no portion of sample support arm 52 is intersected by rotationaxis 44 while the sample is being prepared in the ion beam. When in theretained position, sample holder 50 locates sample 6 in a predeterminedposition and orientation so that at least a portion of the ion beam mayprepare the sample.

With continuing reference to FIG. 1, the ion beam preferably comprisesnoble gas ions. Non-noble gas ions may be used in other preferredembodiments. Noble gas elements used for the ion beam may include butare not limited to: Argon, Xenon, and Krypton. The ion beam may alsocomprise a mixture of ions and neutrals. The position and direction ofion beam irradiating means 20 may be changed so that the angle ofincidence of the central ion beam axis to the sample may be changed. Inpreferred embodiments the angle of incidence may have a range of aroundplus or minus 10 degrees of horizontal. Higher angles of incidenceremove material from the sample more quickly while lower angles ofincidence produce a smoother surface with fewer artifacts. Ion beamintensity control means 24 is operative to control ion beam irradiatingmeans 20 such that one or more of the following properties of the ionbeam may be controlled: energy of the ions produced, number of ionsproduced per unit time, divergence of the emitted ion beam, and spatialdistribution and shape of the emitted ion beam.

Rotation stage 40 is disposed in vacuum chamber 10 in a predeterminedposition and orientation with respect to central ion beam axis 22.During preparation of the sample, rotation drive 42 may control therotation of rotation stage 40 around rotation axis 44. Also, duringpreparation of the sample, ion beam intensity control means 24 may varythe intensity of the ion beam so that at least two different beamintensities may be used during sample preparation. In addition, duringpreparation of the sample, ion beam tilt control means 26 may vary thetilt angle of the ion beam so that at least two different tilt anglesmay be used during sample preparation. After the sample has beenprepared in the ion beam, chamber cover 18 may be removed; then thesample holder may be removed and the prepared sample may be observed ina microscope.

Rotation drive 42 may be configured to rotate rotation stage 40 througha full 360° of rotation or to rock rotation stage 40 back and forthbetween two distinct angular positions. In addition, rotation drive 42may be configured for either continuous or intermittent rotation.Rotation drive 42 may be further configured to measure the rotationalposition of rotation stage 40 and that measurement or sequence ofmeasurements to control position, speed, or acceleration of rotationstage 40.

FIG. 2 shows an embodiment similar to that shown in FIG. 1, having afirst ion beam irradiating means 20 a and a second ion beam irradiatingmeans 20 b, with first ion beam irradiating means having a first centralion beam axis 22 a and second ion beam irradiating means having a secondcentral ion beam axis 22 b. The embodiment of FIG. 2 further comprises:a first ion beam intensity control means 24 a, which is operative toprovide at least two different intensities from first ion beamirradiating means 20 a; a first ion beam tilt control means 26 a, whichis operative to provide at least two different tilt angles of ion beamirradiating means 20 a; and a second ion beam intensity control means 24b, which is operative to provide at least two different intensities fromsecond ion beam irradiating means 20 b; a second ion beam tilt controlmeans 26 b, which is operative to provide at least two different tiltangles of ion beam irradiating means 20 b.

The apparatus of FIG. 2 shows sample 6 being prepared by both first ionbeam irradiating means 20 a and second ion beam irradiating means 20 b.Sample 6 is shown in FIG. 2 as having a first sample surface 9 a and asecond sample surface 9 b. The embodiment of FIG. 2 shows first ion beamirradiating means 20 a preparing first sample surface 9 a while secondion beam irradiating means 20 b is preparing second sample surface 9 b.The preferred embodiment shown in FIG. 2 makes it clear that havingmultiple ion beam irradiating means enables the apparatus to preparemore than one side of sample 6 at a time and thereby offers speed andefficiency improvements over a single ion beam irradiating means. Inother preferred embodiments more than one ion beam may prepare the sameside of the sample.

Turning now to FIG. 3, shown is a perspective view of sample holder 50.Sample holder 50 is shown comprising sample holder retained portion 51,a portion of which may be releasably retained by the sample holderretention means of adjustable positioning stage 45 when the sampleholder is disposed in the vacuum chamber for sample preparation, andfirst sample support arm 52 a and second sample support arm 52 b, whichtogether support and position sample 6. Sample 6 of FIG. 3 is shownhaving a sample surface 9 and a sample peripheral edge 8. When sample 6is being prepared in the ion beam a portion of the beam will be directedat sample surface 9, thereby achieving, through the action of the ionbeam, both polishing and thinning of sample 6. Sample peripheral edge 8typically has a smaller dimension than sample surface 9. Prior topreparation, sample 6 will typically have a thin, disk-like, appearance.Also visible in FIG. 3 is sample holder bore 54, which has a generallyhollow aspect allowing an unobstructed line of sight from the bottomsurface of sample 6 down through the entirety of sample holder retainedportion 51. When sample holder 50 is in a retained position, therotation axis of the rotation stage passes through sample holder bore 54without intersecting any part of sample holder 50.

Now with reference to FIG. 4, shown is a close-up perspective view ofthe portion of rotating stage 40 that is coupled to adjustablepositioning stage 45. During the operation of ion beam samplepreparation apparatus 2, rotation stage 40 is in a predeterminedlocation within vacuum chamber 10. Adjustable positioning stage 45 ismovably coupled to rotation stage 40, thereby enabling adjustment of theposition of sample holder retention means 49. The adjustable positioningstage 45 of FIG. 4 comprises: a first position adjustment means 48 awhich is configured to move the adjustable positioning stage along afirst adjustment axis 46 a, and a second position adjustment means 48 bwhich is configured to move the adjustable positioning stage along asecond adjustment axis 46 b, and a sample holder retention means 49,which releasably retains sample holder 50 in the apparatus while thesample is being prepared in one or more ion beams.

Adjustment of first position adjustment means 48 a causes adjustablepositioning stage 45 to move with respect to rotation stage 40 alongfirst adjustment axis 46 a. In a similar fashion, adjustment of secondposition adjustment means 48 b causes adjustable positioning stage 45 tomove with respect to rotation stage 40 along second adjustment axis 46b. First and second position adjustment means thereby accomplishmicro-positioning of sample holder retention means 49 along first andsecond adjustment axes. When a sample holder is retained in adjustablepositioning stage 45, the position of the sample holder and the positionof any sample that may be held by the sample holder may be adjustedusing first and second position adjustment means 48 a and 48 b.

In preferred embodiments, position adjustment means may allow a range ofmovement along the adjustment axis of about 0.5 millimeters, andincremental adjustments along an adjustment axis can be made,repeatably, as small as 25 micrometers. In other preferred embodimentsposition adjustment means may allow a range of movement along theadjustment axis of a few millimeters. In other preferred embodiments,incremental adjustments along an adjustment axis can be made with theposition adjustment means, repeatably, as small as 10 micrometers. Anumber of constructions of the adjustable positioning means are possiblein which the adjustments may be made by the hand of the operator,including, but not limited to: rack and pinion action; fine-pitchlead-screw action; and, cam and cam-follower action. In addition,electromechanical position adjustment means are also within the spiritand scope of this disclosure including, but not limited to:piezoelectric stepper motor action; stepper motor action; and, servomotor action.

First and second position adjustment means 48 a, and 48 b, respectively,may be adjusted both prior to installing sample holder and after thesample holder has been installed. When sample holder 50 has beeninstalled into adjustable positioning stage 45, the position of thesample holder may be adjusted using first and second position adjustmentmeans 48 a and 48 b.

In preferred embodiments, first adjustment axis 46 a is positioned to besubstantially perpendicular to rotation axis 44, and second adjustmentaxis 46 b is positioned to be substantially perpendicular to rotationaxis 44. In preferred embodiments, first adjustment axis 46 a and secondadjustment axis 46 b are positioned substantially perpendicular to eachother. The cumulative result of first and second position adjustingmeans is to allow sample 6 to move within the vacuum chamber relative tothe position and direction of one or more ion beams so that differentareas of sample 6 may be prepared by the one or more ion beams.

FIG. 5 shows a perspective view in which sample holder retained portionis engaged in sample holder retention means. In preferred embodiments,sample holder retention means 49 may releasably retain sample holder 50using a friction fit or a spring loaded mechanism. Alternateconstructions of sample holder retention means 49 include, but are notlimited to threaded and clamping mechanisms. When sample holder 50 isretained in adjustable positioning stage 45, any adjustment made tofirst position adjustment means 48 a will move sample 6 along thedirection of first adjustment axis 46 a. Also, any adjustment made tosecond position adjustment means 48 b will move sample 6 along thedirection of second adjustment axis 46 b. FIG. 5 further shows thatfirst and second position adjustment means may be accessed and adjustedwhile sample holder 50 is in the retained position on adjustablepositioning stage 45.

FIG. 6 shows a perspective view of the apparatus of FIG. 5 in which apositioning stage cover 47 has been placed on rotation stage 40 in sucha way as to cover the adjustable positioning stage and thereby protectthe adjustable positioning stage from sputtered debris as the sample isbeing prepared by one or more ion beams. Positioning stage cover 47 isfurther characterized in that it may be installed and removed whilesample holder 50 is retained, and it may be removed and reinstalledwithout moving or otherwise disturbing or touching sample 6.

Turning now to FIG. 7A, shown is a schematic cross sectional view of anion beam sample preparation apparatus according to another embodiment ofthe present disclosure, having features that enable viewing of thesample while it is being prepared by the ion beam. The apparatus of FIG.7A additionally discloses: a vacuum chamber cover 18 comprising: avacuum tight, optically transparent vacuum window 70, a shutter means 72disposed between vacuum window 10 and sample holder 50, shutter means 72further characterized as having both a shutter closed position, in whichvacuum window 70 is substantially sealed from the interior of vacuumchamber 10, and a shutter open position, in which direct, line-of-sightviewing of sample 6 is permitted from outside vacuum chamber 10, throughvacuum window 70, and onto sample 6 as it is being prepared by one ormore ion beams; a sample viewing means 71 having an optical axis 76directed toward the region of sample 6 being prepared by one or more ionbeams, sample viewing means 71 further characterized as providing amagnified and substantially focused view of the region of the samplebeing prepared by one or more ion beams; a first illumination source 60a, which directs light toward first sample surface 9 a, and in which atleast a portion of the light strikes the region of sample 6 beingprepared by one or more ion beams; and a second illumination source 60b, which directs light toward second sample surface 9 b, and in which atleast a portion of the light strikes the region of sample 6 beingprepared by one or more ion beams.

In the apparatus of FIG. 7A, the rotation stage 40 and adjustablepositioning stage are configured to allow at least a portion of lightfrom first illumination source 60 a to pass through the sample holderbore and strike first sample surface 9 a in the region where the sampleis being prepared by one or more ion beams. In preferred embodiments,first and second illumination sources 60 a and 60 b, respectively,comprise light emitting diodes (LEDs) emitting substantiallymono-chromatic light, light with a broad color spectrum, or anycombination both mono-chromatic and broad spectrum. In preferredembodiments, sample viewing means 71 is an optical microscope withappropriate focal length and magnification to view the region of thesample being prepared.

It can be appreciated, with reference to FIG. 7A, that when shuttermeans 72 is in the shutter closed position, vacuum window 70 isprotected from being fouled or clouded by sputtered material that may beproduced in the apparatus as a sample is being prepared by the one ormore ion beams. Shutter means 72 may be manipulated into the shutteropen position, as shown in FIG. 7B, when the operator desires to viewthe progress of the sample using sample viewing means 71. After sampleviewing, shutter means 72 may be returned to the shutter closed positionof FIG. 7A, thereby minimizing the amount of sputtered material allowedto build up on vacuum window 70.

Use of the apparatus shown in FIG. 1 through FIG. 7B may proceed withreference to the following steps: outside of the vacuum chamber a samplemay be mounted to a sample holder; with the chamber cover removed, thesample and sample holder combination may be set in the sample holderretention means of the adjustable positioning stage, and the first andsecond position adjustment means may be adjusted by the operator to movethe sample to a position; if desired, the positioning stage cover maythen be placed over the adjustable positioning stage; the chamber covermay then be replaced; the vacuum pump means may then be operated toevacuate the vacuum chamber through the pumping manifold, therebyobtaining vacuum levels appropriate for ion beam milling; the ion beamirradiating means may then be operated to prepare the sample.Periodically, the operator of the apparatus may check on the progressand location of the prepared portion of the sample. If the apparatus isequipped with vacuum window, shutter, illumination, and sample viewingmeans, then the shutter may be opened and the sample viewed directly bythe operator without needing to remove the chamber cover. If theapparatus is not equipped with vacuum window etc., then the chamber canbe opened to inspect the progress of the sample preparation. If theoperator judges that the desired region of the sample is not beingprepared, then the operator may determine that the first or secondposition adjustment means need to be adjusted to expose and prepare thedesired sample region. If necessary, ion beam irradiating means may beturned off, the vacuum chamber may be returned to ambient atmosphericpressure, the chamber cover removed, the positioning stage cover removedif necessary, and then the first and second position adjusting means maybe adjusted by the operator to adjust the position of the sample. Thesample may then be returned to the vacuum chamber and the processrepeated as needed until the sample is prepared as desired. A microscopemay be then fitted with the sample holder for observation of thesample's region of interest.

Shown now in FIG. 8A is a schematic cross sectional view of an ion beamsample preparation apparatus 2 according to another embodiment of thepresent disclosure, featuring a rotation stage lifting means 80. In theapparatus of FIG. 8A, a rotation stage lifting means is shown in araised position 86. While in raised position 86, sample holder 50 may beinstalled or removed from adjustable positioning stage 45. Also, whilein raised position 86, first position adjustment means and secondposition adjustment means of the adjustable positioning stage 45 may beadjusted, thereby facilitating the preparation of a region of interestin sample 6. The apparatus of FIG. 8A is shown comprising: a vacuumchamber 10, in which a sample may be prepared; a removable andreplaceable chamber cover 18, having an optically transparent vacuumwindow 70; an ion beam irradiating means 20, which creates and directsan ion beam having a central ion beam axis 22 toward sample 6; an ionbeam intensity control means 24, which is operative to provide at leasttwo different ion beam intensities; an ion beam tilt control means 26,which is operative to provide at least two different tilt angles of ionbeam irradiating means 20; a first pumping manifold 92 a and a pumpingmeans 90, which together bring vacuum chamber 10 to vacuum levelsappropriate for ion beam milling; a rotation stage 40 coupled to anadjustable positioning stage 45, in which sample holder 50 may be held;a rotation stage lifting means 80 which is operably coupled to rotationstage 40, rotation stage lifting means 80 being further characterized inhaving a raised position 86, in which vacuum sealing features engagebetween vacuum chamber 10 and rotation stage 40 to maintain vacuumconditions inside vacuum chamber 10; a shutter means 72 having a shutteropen position and a shutter closed position, the shutter open positionfurther characterized as permitting a direct, line-of-sight viewing ofsample 6 from outside vacuum chamber 10, through vacuum window 70, andonto sample 6 as it is being prepared by the ion beam; a shutteractuation 73 means operably coupled to shutter means 72 to provide botha shutter open position and a shutter closed position; and, a firstillumination source 60 a, which directs light toward sample 6, at leasta portion of which strikes the sample.

FIG. 8B shows the apparatus of FIG. 8A with chamber cover 18 installedon vacuum chamber 10 and thereby creating loading chamber 16, which isisolated from both the outside atmosphere and the remainder of vacuumchamber 10. In a preferred embodiment, when chamber cover 18 is in placeto seal the loading chamber from the outside atmosphere, the volume ofloading chamber 16 is substantially smaller than the volume of vacuumchamber 10. When the apparatus is configured as in FIG. 8B, secondpumping manifold 92 b and pumping means 90 may be used to evacuateloading chamber 16 in preparation for lowering sample 6 into theprocessing position.

FIG. 8C shows the same apparatus as FIG. 8A and FIG. 8B, however,rotation stage lifting means 80 has operated to move the rotation stageinto a processing position 88. When in processing position 88, rotationdrive 42 is engaged with rotation stage 40 and is operable to rotatearound rotation axis 44. Processing position 88 disposes sample 6 in aposition where one or more surfaces of sample 6 may be processed by theion beam. FIG. 8C further shows shutter means 72 in a shutter closedposition, in which vacuum window 70 may be isolated from the rest ofvacuum chamber 10 thereby minimizing the amount of sputtered materialallowed to build up on vacuum window 70.

FIG. 8D shows the same apparatus as FIG. 8A, FIG. 8B, and FIG. 8C,however, shutter actuation means 73 has operated to move shutter means72 into a shutter open position that allows direct, line-of-sightviewing, through vacuum window 70 and onto the sample being prepared inthe ion beam. When necessary, the sample may be viewed while undergoingprocessing through vacuum window 70 with the shutter means 72 in ashutter open position. A variety of means may be used to view the sampleincluding, but not limited to: optical microscope, still camera, digitalimage capture, video, and other means of capturing images for eitherimmediate or time-delayed analysis.

In can be appreciated that the apparatus of FIGS. 8A, 8B, 8C, and 8Dallows certain desirable efficiencies. Instead of venting the entirevacuum chamber when a positioning adjustment of the sample needs to bemade, rotation stage lifting means 80 may be operated to raise thesample into the loading chamber 16. In preferred embodiments, the volumeof the loading chamber is much smaller that the volume of the vacuumchamber. Vacuum conditions are maintained in the remainder of the vacuumchamber when the rotation stage is in the raised position. Venting andevacuating the small volume of the loading chamber takes much less timethan it does to vent and evacuate the entire chamber. When the loadingchamber has been evacuated to pressures appropriate for ion beammilling, the rotation stage lifting means may be operated to move thesample into the processing position, and the sample may again beprepared in the ion beam.

Turning now to FIG. 9, shown is an embodiment of the apparatus of FIG.8A through FIG. 8D which additionally comprises: a sample imaging means74 having an optical axis 76 directed toward the region described by theintersection of rotation axis 44 with sample 6; a second illuminationsource 60 b, which directs light toward sample 6, at least a portion ofwhich strikes the sample; an instrument controller 100 which:communicates with and coordinates the actions of sample imaging means 74through first communications channel 102 a; communicates with andcoordinates the actions of shutter actuation means 73 through secondcommunications channel 102 b; communicates with and coordinates theactions of ion beam intensity control means 24 through thirdcommunications channel 102 c; communicates with and coordinates theactions of ion beam tilt control means 26 through fourth communicationschannel 102 d; communicates with and coordinates the actions of rotationdrive 42 through fifth communications channel 102 e.

The ion beam sample preparation apparatus 2 shown in FIG. 9 enablesnumerous improvements in both the quality of prepared samples and in theefficiency of their preparation. Sample imaging means 74 may takedifferent forms with different features, as may be appropriate for theimaging task. In preferred embodiments, sample imaging means 74 isoperable to acquire images and communicate image data to instrumentcontroller 100. Sample imaging means 74 may also process acquiredimages, extract features from the acquired images, and communicate thoseextracted features to instrument controller 100. Instrument controller100 may then use image data, processed image data, and featuresextracted from image data in controlling those subsystems with whichinstrument controller 100 may be in communication. Instrument controller100 may also store image data, processed image data, and extracted imagefeatures for later use.

In preferred embodiments, sample imaging means 74 comprises: a digitalimage sensor, a lens system coupled to said digital image sensor andfocused on at least a portion of the sample being prepared in the ionbeam; and a zoom capability which may be either optical in nature so asto operate on the lensing system, or digital in nature so as to operateon the digital image that is acquired. In preferred embodiments, firstcommunications channel 102 a carries data bidirectionally betweeninstrument controller 100 and sample imaging means 74. Instrumentcontroller 100 may thereby both trigger the acquisition of imagesthrough sample imaging means 74 and receive data derived from the act ofacquiring an image. In certain preferred embodiments, sample imagingmeans 74 may control first illumination source 60 a and secondillumination source 60 b, and thereby have greater control over thequality of the sample image acquired. Sample imaging means 74 mayadditionally comprise an operator display which may show an operator ofthe apparatus an image or sequence of images from the sample as it isbeing prepared in the ion beam. Sample imaging means 74 may additionallydisplay stored images acquired previously.

In other preferred embodiments, images acquired by sample imaging means74 may be processed to extract features of interest relating to theprocess of preparing a sample in the ion beam. In one preferredembodiment, first illumination source 60 a may provide illumination ofsample 6 as sample imaging means 74 acquires an image. As the sample isbeing processed by the ion beam, it will gradually become thinner.Eventually a perforation of the sample will start to form. When thesample is backlit, such a perforation will show up as a bright spot,whereas non-perforated regions of the sample will show up much darker onan image. In another preferred embodiment, first and second illuminationsources 60 a and 60 b, respectively, may illuminate the sample. As thesample thins, but prior to the perforation of the sample, interferencerings located around the thinnest area of the sample may become visibleon an image. In addition, color changes of the interference rings may beobserved prior to the perforation of the sample by the ion beam. Theseimages features, and others, may be extracted from a captured image orsequence of images and may be used by instrument controller 100 in theoperation of the apparatus.

Through second communications channel 102 b, instrument controller 100is operative to control shutter actuation means 73, and thereby provideat least two positions of shutter means 72. In addition, secondcommunications channel 102 b may be operative to send data to instrumentcontroller 100 that may indicate what position shutter means 72 may bein. Instrument controller 100 may thereby both control and observe theoperation of shutter actuation means 73 and shutter means 72.

Through third communications channel 102 c, instrument controller 100 isoperative to control ion beam intensity control means 24, therebyproviding at least two different intensities of ion beam. Thirdcommunications channel 102 c may carry bidirectional data betweeninstrument controller 100 and ion beam intensity control means 24, andmay thereby both control and observe the operation of ion beam intensitycontrol means 24.

Through fourth communications channel 102 d, instrument controller 100is operative to control ion beam tilt control means 26, therebyproviding at least two different tilt angles of the ion beam. Fourthcommunications channel 102 d may carry bidirectional data betweeninstrument controller 100 and ion beam tilt control means 26, and maythereby both control and observe the operation of ion beam tilt controlmeans 26.

Through fifth communications channel 102 e, instrument controller 100 isoperative to control rotation drive 42. Instrument controller 100 maythereby control the position, speed, and acceleration of rotation stage40. Fifth communications channel 102 e may carry bidirectional databetween instrument controller 100 and rotation drive 42 so thatinstrument controller 100 may both control and observe the operation ofrotation stage 40.

FIG. 10 shows a flowchart of the operation of the apparatus of FIG. 9according to a preferred embodiment of the disclosure. The process stepsof FIG. 10 can be understood with reference to instrument controller 100acting as both observer and controller of the subsystems of theapparatus. Starting with process step of prepare for acquisition 200,instrument controller 100 starts to prepare the apparatus to capture animage of the sample being prepared. In preferred embodiments,acquisition trigger? 200 may happen at predetermined times or atpredetermined rotation angles. The process then moves to process stepopen shutter 202, during which time shutter means 72 may be caused tomove to the shutter open position. Moving on to process step acquireimage 204, sample imaging means 74 may be caused to acquire an image,after which process step close shutter 206 may move shutter means 72 tothe shutter closed position. Process step extract image features 208 maythen extract features of interest from the newly acquired image. If oneor more of the extracted features indicate that the sample is finished,then process step detect stopping condition? 210 identifies the stoppingcondition and stops the process. If no stopping condition was detected,then the process moves on to process step detect condition requiringadjustment? 212 to decide if any adjustments must be made to theapparatus. If no adjustments are necessary, then the process transitionsback to process step acquisition trigger? 200 and repeats. If adjustmentis necessary, then one or any combination of the following three processsteps may be triggered: adjust beam intensity 214; adjust rotation drive216; and, adjust beam angle 218. After adjustments are made, the processtransitions back to process step acquisition trigger? 200 and repeats.During process step adjust beam intensity 214, ion beam intensitycontrol means 24 may be caused to increase or decrease the intensity ofthe ion beam. During process step adjust rotation drive 216, rotationdrive 42 may be caused to increase or decrease the rotational position,the rotation speed, or the acceleration of rotation stage 40. Duringprocess step adjust beam angle 218, ion beam tilt control means 26 maybe caused to adjust the angle with which central ion beam axis 22strikes sample 6.

Process step acquire image 204 can now be better understood withreference to the flowchart of FIG. 11. The flowchart of FIG. 11 showsthat a number of sub-steps may be beneficially performed to complete theprocess step of acquire image 204. In process step determine acquisitionparameters 300, sample imaging means 74 retrieves or derives parameterswhich control the acquisition of the image. Then process step adjustillumination 302 uses retrieved or determined parameters to adjust theillumination provided by first illumination source 60 a, or secondillumination source 60 b, or both illumination sources. Process stepadjust focus 304 then uses retrieved or determined parameters to adjustthe focus properties of sample imaging means 74. Process step adjustzoom 306 uses retrieved or determined parameters to adjust the zoomproperties of sample imaging means 74. Process step adjust exposure 308uses retrieved or determined parameters to adjust exposure properties ofsample imaging means 74. Process step adjust rotation drive 310 mayadjust the position, speed, and acceleration of the rotation stage,according to retrieved or determined parameters. In preferredembodiments the apparatus may slow down or stop the rotation stage priorto image capture. Next, the apparatus waits at process step acquisitiontrigger? for a precisely predetermined time or a precisely determinedrotation angle to occur. When acquisition trigger? does occur theprocess will transition to process step capture image 314, where theimage will be captured. The image may be stored to nonvolatile storageor sent via communication channel elsewhere for other uses. Aftercapture is complete the process advances to process step adjustillumination 316 so that the first and second illumination sources maybe adjusted, which may include being turned off. Thereafter, the processembodied by the flowchart of FIG. 11 is complete.

The apparatus of FIG. 9 makes many beneficial capabilities and featurespossible. One preferred benefit is that sequences of images may becaptured. When one or more ion beams are directed at the sample, imagingmeans 74 may capture sequential images of the sample which willcorrespond to deeper and deeper regions of the sample because the ionbeam is removing material from the sample between successive images. A3D reconstruction of the sample may therefor be made from a sequence ofimages acquired by the embodiment of FIG. 9.

Additional image processing may be used on acquired images. In apreferred embodiment, images captured at different rotation angles mayeach be programmatically rotated by instrument controller 100 to appearas though all images were captured at the same angle. Sequences ofimages processed in this way would not appear to rotate at all as thesample is being processed and images are being acquired. When viewed byan operator, images processed in the way described greatly enhance theusability of the apparatus.

Turning now to FIG. 12, shown is a flowchart of a beneficial aspect ofanother embodiment according to the present disclosure. The process ofFIG. 12 may be carried out by an operator of the ion beam samplepreparation apparatus 2 of FIG. 9 in which instrument controller 100further comprises: a display system for presenting an image to anoperator; an input system operable to accept annotations created by anoperator; and a storage system operable to save the annotation data withthe image. When a sample has been prepared it is often very useful tohave a way of recording where the region of interest is or where variousfeatures of interest are in the prepared sample. This can be efficientlydone by an operator of the ion beam apparatus by following the processof FIG. 12. First process step annotate image 400 is started. Based uponoperator selection, or automatically at the end of sample processing,process step present image 402 may present an image that was acquired bysample imaging means 74 to the operator by means of the display systemof instrument controller 100. In process step accept image annotation404, the operator may enter one or more pieces of annotation data usingthe input system of instrument controller means 100. In preferredembodiments annotation data may specify one or any combination of thefollowing: x and y coordinates of one or more points of interest, uniqueindicia for each annotation accepted such as incremental numbering orlettering, centroid location of one or more features of interest, thelocation and extent of a two dimensional sub region of the imagecontaining one or more features of interest, and a classification orother description of the type of feature present in the currentannotation. Annotations may be in the form of human readable text,graphics, and images, or may be in a machine readable format adapted tofacilitate exchange with other equipment. Process step stop annotation?406 permits a plurality of annotations to be made for each image. Whenno more annotations need to be made, process step save annotations withimage 408 saves all annotations in the storage system of instrumentcontroller 100 in such a way that the annotations are associated withthe image. Process step annotation complete 410 ends this process.

A sample which has been prepared in the ion beam, has been imaged, andalso has been annotated according to the process of FIG. 12 maythereafter be transferred to a microscope for observation. The operatorof the microscope may derive significant benefits from using theannotated image when locating, magnifying, focusing, and observing thesample in the microscope equipment.

Although the present invention has been described in considerable detailwith reference to certain preferred versions thereof, other versions arepossible. It may be desirable to combine features shown in variousembodiments into a single embodiment. A different number andconfiguration of features may be used to construct embodiments of ionbeam sample preparation apparatus that are entirely within the spiritand scope of the present disclosure. Therefor, the spirit and scope ofthe appended claims should not be limited to the description of thepreferred versions contained herein.

Any element in a claim that does not explicitly state “means for”performing a specified function, or “step for” performing a specificfunction, is not to be interpreted as a “means” or “step” clause asspecified in 35 U.S.C. Section 112, Paragraph 6. In particular, the useof “step of” in the claims herein is not intended to invoke theprovisions of 35 U.S.C. Section 112, Paragraph 6.

The invention claimed is:
 1. An ion beam sample preparation apparatuscomprising: a) a first ion beam irradiating means disposed in a vacuumchamber and directing a first ion beam toward said sample, said firstion beam irradiating means operatively coupled to a first ion beamintensity control means, said first ion beam having a first central ionbeam axis, said first ion beam intensity control means operative toproduce at least two different ion beam intensities; b) a first ion beamtilt control means operatively coupled to said first ion beamirradiating means and configured to provide at least two different tiltangles of said first ion beam irradiating means; c) a rotation stagedisposed inside said vacuum chamber having a rotation axis and coupledto a rotation drive, said rotation drive operative to rotate saidrotation stage around said rotation axis, said rotation axis beingpositioned to intersect a portion of said first ion beam; d) anadjustable positioning stage that is adjustably coupled to said rotationstage, said adjustable positioning stage comprising a sample holderretention means configured to releasably retain a sample holder, saidsample holder comprising: a sample holder retained portion; at least onesample support arm configured to support said sample; and a sampleholder bore that allows an unobstructed line of sight through theentirety of sample holder retained portion onto said sample being heldby said one or more sample support arms; said sample holder furthercharacterized as positioning said sample so that said rotation axis andsaid first central ion beam axis both intersect substantially the sameportion of said sample that is being prepared in said first ion beam;said sample holder further characterized in that no portion of saidsample support arm is intersected by said rotation axis while saidsample is being prepared by said ion beam; e) said adjustablepositioning stage further comprising: a first position adjustment meansconfigured to move said adjustable positioning stage along a firstadjustment axis; and, a second position adjustment means configured tomove said adjustable positioning stage along a second adjustment axis;f) a vacuum-tight optically-transparent vacuum window disposed to permitdirect, line-of-sight viewing from outside the vacuum chamber of atleast a portion of said sample while said sample is being prepared insaid first ion beam; and, a shutter means disposed between said vacuumwindow and said sample holder; said shutter means further characterizedas having a shutter closed position in which said vacuum window issubstantially sealed from the interior of said vacuum chamber, and saidshutter means further characterized as having a shutter open positionthat permits direct, line-of-sight viewing from outside the vacuumchamber of at least a portion of said sample while said sample is beingprepared in said first ion beam; g) a first illumination sourcedirecting light through said sample holder bore toward said sample andfurther characterized in that at least a portion of the light emitted bysaid first illumination source strikes at least a portion of said samplewhile said sample is being prepared in said first ion beam; h) a sampleviewing means having an optical axis directed toward the region wheresaid first central ion beam axis substantially intersects said rotationaxis, said sample viewing means further characterized as providing amagnified and substantially focused view of the region of said samplebeing prepared by said first ion beam.
 2. The apparatus of claim 1 inwhich said first illumination source is further characterized asproducing substantially monochromatic light.
 3. The apparatus of claim 1further comprising: a second illumination source directing light towardsaid sample and further characterized in that at least a portion of thelight emitted by said second illumination source strikes at least aportion of said sample while said sample is being prepared in said firstion beam.
 4. The apparatus of claim 1 further comprising: a sampleimaging means that is operative to capture one or more images madeavailable by said sample viewing means.
 5. The apparatus of claim 4 inwhich said sample imaging means is operative to save one or morepreviously captured images.
 6. The apparatus of claim 5 furthercharacterized in that the sample imaging means is operative to save oneor more unique indicia with each said one or more previously capturedimages.
 7. The apparatus of claim 6 in which said sample imaging meansis operative to display said one or more previously captured images. 8.The apparatus of claim 7 further characterized in that the sampleimaging means is operative to receive said one or more unique indiciaand display said one or more previously captured images correspondingwith said one or more unique indicia.
 9. The apparatus of claim 7further characterized in that the sample imaging means is operative toreceive one or more annotations identifying the location of one or moreregions of interest within said one or more previously captured imagesand saving said one or more annotations with said one or more previouslycaptured images.
 10. An ion beam sample preparation apparatuscomprising: a) a first ion beam irradiating means disposed in a vacuumchamber and directing a first ion beam toward said sample, said firstion beam irradiating means operatively coupled to a first ion beamintensity control means, said first ion beam having a first central ionbeam axis, said first ion beam intensity control means operative toproduce at least two different ion beam intensities; b) a first ion beamtilt control means operatively coupled to said first ion beamirradiating means and configured to provide at least two different tiltangles of said first ion beam irradiating means; c) a rotation stagedisposed inside said vacuum chamber having a rotation axis and coupledto a rotation drive, said rotation drive operative to rotate saidrotation stage around said rotation axis, said rotation axis beingpositioned to intersect a portion of said first ion beam; d) anadjustable positioning stage that is adjustably coupled to said rotationstage, said adjustable positioning stage comprising a sample holderretention means configured to releasably retain a sample holder, saidsample holder comprising: a sample holder retained portion; at least onesample support arm configured to support said sample; and a sampleholder bore that allows an unobstructed line of sight through theentirety of sample holder retained portion onto said sample being heldby said one or more sample support arms; said sample holder furthercharacterized as positioning said sample so that said rotation axis andsaid first central ion beam axis both intersect substantially the sameportion of said sample that is being prepared in said first ion beam;said sample holder further characterized in that no portion of saidsample support arm is intersected by said rotation axis while saidsample is being prepared by said ion beam; e) said adjustablepositioning stage further comprising: a first position adjustment meansconfigured to move said adjustable positioning stage along a firstadjustment axis; and a second position adjustment means configured tomove said adjustable positioning stage along a second adjustment axis;f) a vacuum-tight optically-transparent vacuum window disposed to permitdirect, line-of-sight viewing from outside the vacuum chamber of atleast a portion of said sample while said sample is being prepared insaid first ion beam; and a shutter means disposed between said vacuumwindow and said sample holder; said shutter means further characterizedas having a shutter closed position in which said vacuum window issubstantially sealed from the interior of said vacuum chamber, and saidshutter means further characterized as having a shutter open positionthat permits direct, line-of-sight viewing from outside the vacuumchamber of at least a portion of said sample while said sample is beingprepared in said first ion beam; g) a first illumination sourcedirecting light toward said sample and further characterized in that atleast a portion of the light emitted by said first illumination sourcestrikes at least a portion of said sample while said sample is beingprepared in said first ion beam; h) a sample viewing means having anoptical axis directed toward the region where said first central ionbeam axis substantially intersects said rotation axis, said sampleviewing means further characterized as providing a magnified andsubstantially focused view of the region of said sample being preparedby said first ion beam; i) a sample imaging means that is operative tocapture one or more images made available by said sample viewing means,said sample imaging means further characterized as being operativelycoupled to a first communications channel and being responsive to saidcommunications channel for capturing one or more images andcommunicating one or more captured images over said first communicationschannel; j) an instrument controller that is operative to: communicatewith and control the actions of said sample imaging means through saidfirst communications channel; communicate with and control the actionsof a shutter actuation means through a second communications channel,said shutter actuation means being operative to move said shutter meansbetween said shutter open position and said shutter closed position inresponse to communications received through said second communicationschannel.
 11. The apparatus of claim 10 further characterized in that theinstrument controller is operative to communicate with and control theactions of said first ion beam intensity control means through a thirdcommunications channel, the first ion beam intensity control means beingoperative to change the intensity of said first ion beam in response tocommunications received through said third communications channel. 12.The apparatus of claim 10 further characterized in that the instrumentcontroller is operative to communicate with and control the actions ofsaid first ion beam tilt control means through a fourth communicationschannel, said first ion beam tilt control means being operative tochange the intensity of said first ion beam in response tocommunications received through said fourth communications channel. 13.The apparatus of claim 10 further characterized in that the instrumentcontroller is operative to communicate with and control the actions ofsaid rotation drive through a fifth communications channel, saidrotation drive being operative to change the position of said rotationstage in response to communications received through said fifthcommunications channel.
 14. The apparatus of claim 10 furthercharacterized in that: a) the instrument controller is operative tocommunicate with and control the actions of said first ion beamintensity control means through a third communications channel, thefirst ion beam intensity control means being operative to change theintensity of said first ion beam in response to communications receivedthrough said third communications channel; b) the instrument controlleris operative to communicate with and control the actions of said firstion beam tilt control means through a fourth communications channel,said first ion beam tilt control means being operative to change theintensity of said first ion beam in response to communications receivedthrough said fourth communications channel; and c) the instrumentcontroller is operative to communicate with and control the actions ofsaid rotation drive through a fifth communications channel, saidrotation drive being operative to change the position of said rotationstage in response to communications received through said fifthcommunications channel.
 15. The apparatus of claim 14 furthercharacterized in that the instrument controller is operative to extractone or more features from one or more captured images, and in responseto one or more extracted features said instrument controller isoperative to control at least one of the group consisting of said sampleimaging means, said shutter actuation means, said first ion beamintensity control means, said first ion beam tilt control means, andsaid rotation drive.
 16. The apparatus of claim 15 further characterizedin that the instrument controller is operative to extract a feature fromone or more captured images that indicates that said sample isperforated, said instrument controller being further characterized asbeing operative to respond to the extraction of said feature by causingsaid first ion beam intensity control means to change the ion beamintensity.
 17. The apparatus of claim 15 further characterized in thatthe instrument controller is operative to extract a feature from one ormore captured images that represents a stopping condition, and inresponse to extracting said stopping condition said instrumentcontroller is operative to cease preparing said sample in said first ionbeam.
 18. The apparatus of claim 15 further characterized in that theinstrument controller is operative to extract a feature from one or morecaptured images that indicates that said sample is approachingperforation, said instrument controller being further characterized asbeing operative to respond to the extraction of said feature by causingsaid first ion beam intensity control means to change the intensity ofsaid first ion beam.
 19. The apparatus of claim 15 further characterizedin that the instrument controller is operative to: extract a featurefrom one or more captured images that is representative of one or moreinterference rings; and extract a feature from one or more capturedimages that is representative of a change over time of said one or moreinterference rings; said instrument controller being furthercharacterized as being operative to respond to the extraction of saidfeatures by causing said first ion beam intensity control means tochange the intensity of said first ion beam.
 20. The apparatus of claim14 further characterized in that the rotation drive is operative toprovide a rotation angle to the instrument controller, and theinstrument controller is operative to capture an image and annotate saidcaptured image with said rotation angle.
 21. The apparatus of claim 14further characterized in that the rotation drive is operative to providea rotation angle to the instrument controller, and the instrumentcontroller is operative to capture one or more images at substantiallythe same rotation angle.
 22. The apparatus of claim 21 furthercharacterized in that the instrument controller is operative to use oneor more acquisition parameters to control at least one from the groupconsisting of said sample imaging means, said shutter actuation means,said first ion beam intensity control means, and said first ion beamtilt control means; and said rotation drive, when said shutter means isin said shutter closed position, and the apparatus is furthercharacterized in that the instrument controller is operative to use oneor more acquisition parameters to control at least one of the groupconsisting of said sample imaging means, said shutter actuation means,said first ion beam intensity control means, said first ion beam tiltcontrol means, and said rotation drive, when said shutter means is insaid shutter open position.